How do you figure out left position for a annotation text box

[User (Legacy)]

I want to place a text box above the graph area and have the right side 

of the box in line with the right side (y2 axis which is not visible) of 

the graph.  Is there some formula to figure this out.  Prior to setting 

the left property of the box, I have populated the box with text and 

performed SizeToFit.

Thanks,

Wendy Gatanis